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<TITLE>First look at the JetProb b-tagging algorithm in the 900 GeV collision data with the ATLAS detector</TITLE>
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<H1 ALIGN=CENTER><I>First look at the JetProb b-tagging algorithm in the 900 GeV collision data with the ATLAS detector</I></H1>
<P ALIGN=CENTER><B>ATLAS-CONF-2010-010</B></P><P ALIGN=CENTER>8 March 2010 </P><TABLE WIDTH=800 ALIGN=CENTER CELLPADDING=5 CELLSPACING=1 BGCOLOR=#002000 FRAME=box>
<TR bgcolor=#ffffe0><TH>Content</TH><TH>Preview</TH></TR>
<TR bgcolor=fefefe><TD ALIGN=CENTER><A HREF="ATLAS-CONF-2010-010.pdf">Main document (PDF, 352kB)</A>
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<TR bgcolor=fefefe><TD ALIGN=CENTER><I>Figure 3</I>:<BR>Number of b-tagging quality tracks associated to a jet, for experimental data (black solid points) and for simulated data (plain histogram, normalized to data). Only jets with at least one associated track are considered. The association is done with a cut on DeltaR(track, jet) which varies with the jet pT but is typically 0.5.
<BR><A HREF="fig_3.eps">eps, 923kB</A><BR><A HREF="fig_3.png">png, 309kB</A><BR>
</TD><TD ALIGN=CENTER><IMG SRC=".thumb_fig_3.png"></TR>
<TR bgcolor=fefefe><TD ALIGN=CENTER><I>Figure 4</I>:<BR>Distribution of the transverse impact parameter significance d0/sigma(d0) for tracks with negative d0, for the experimental data (solid points), and for the simulated events (plain histogram, normalized to data) from which the resolution function is built.
 The sign of d0 is defined to be negative if the track crosses the jet axis behind the primary vertex.
<BR><A HREF="fig_4.eps">eps, 638kB</A><BR><A HREF="fig_4.png">png, 680kB</A><BR>
</TD><TD ALIGN=CENTER><IMG SRC=".thumb_fig_4.png"></TR>
<TR bgcolor=fefefe><TD ALIGN=CENTER><I>Figure 5</I>:<BR>Distribution of the transverse impact parameter significance d0/sigma(d0) for the tracks used for tagging jets, i.e. tracks with positive d0. Experimental data are shown as solid black points, the simulated data as a plain histogram (normalized to data).
<BR><A HREF="fig_5.eps">eps, 584kB</A><BR><A HREF="fig_5.png">png, 372kB</A><BR>
</TD><TD ALIGN=CENTER><IMG SRC=".thumb_fig_5.png"></TR>
<TR bgcolor=fefefe><TD ALIGN=CENTER><I>Figure 6</I>:<BR>Distribution of the probability for a tagging track in a jet to come from a primary vertex, for experimental data (solid black points) and for simulated data (plain histogram, normalized to data).
 Heavy-flavoured particles, but also other long-lived particles, would appear in the region of low-probability values.
<BR><A HREF="fig_6.eps">eps, 416kB</A><BR><A HREF="fig_6.png">png, 991kB</A><BR>
</TD><TD ALIGN=CENTER><IMG SRC=".thumb_fig_6.png"></TR>
<TR bgcolor=fefefe><TD ALIGN=CENTER><I>Figure 7</I>:<BR>Distribution of the probability for a jet to be a light-jet, for experimental data (solid black points) and for simulated events (plain histogram, normalized to data).
 Heavy-flavoured particles, but also other long-lived particles, would appear in the region of low probability values. A slight bias towards low-probability values can be seen for experimental data: the agreement between data and simulation for describing the tails of the impact parameter significance can still be improved.
<BR><A HREF="fig_7.eps">eps, 117kB</A><BR><A HREF="fig_7.png">png, 551kB</A><BR>
</TD><TD ALIGN=CENTER><IMG SRC=".thumb_fig_7.png"></TR>
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